Top Alternatives to Rainlendar

Google Calendar is a robust, cloud-based scheduling and time management platform developed by Google. It allows users to create and manage events, set up reminders, share calendars with others, and sync seamlessly across devices, making it an essential tool for personal, academic, and professional organization.

Kontact is a comprehensive personal information management suite from KDE combining email, contacts, calendar, tasks, and news in one integrated application. It offers robust synchronization options and supports various protocols.

Etar is a free and open-source material design calendar application for Android, prioritizing privacy and a clean user experience. It focuses on core calendar functionalities like event management and reminders, offering data export/import and syncing capabilities without ads or excessive features.

VueMinder Calendar is a comprehensive calendar and task management application for Windows, designed to help users organize their schedules and boost productivity. It offers a wide range of features including robust synchronization options, customizable views, and advanced reminder capabilities, making it suitable for both personal and professional use.

Holiline Reminder is a free, multi-language calendar and organizer for Windows, designed to help users manage events, deadlines, tasks, and notes efficiently. It includes features like recurring tasks, an address book, and a built-in calendar, offering a straightforward approach to staying organized.

Osmo is a lightweight and versatile personal organizer designed for efficiency. It integrates essential modules like a color calendar, task manager, address book, and notes editor into a single, user-friendly interface, making it ideal for managing daily activities.

KOrganizer is a comprehensive calendar and scheduling application, part of the integrated KDE Kontact suite. It provides robust tools for managing events, tasks, and deadlines, with extensive connectivity options and customization.